The present invention relates to a scroll fluid machine which is preferably used as an air compressor or a vacuum pump, for example.
As a scroll fluid machine, there is generally known a scroll compressor configured to continuously compress a fluid such as air in compression chambers between an orbiting scroll and a fixed scroll by orbiting the orbiting scroll relative to the fixed scroll without allowing the orbiting scroll to self-rotate on its axis by a drive source such as an electric motor (see JP-A-2006-283673, for example).
In this type of scroll compressor according to the related art, three ball coupling devices are provided between a casing of the compressor and the orbiting scroll, thereby receiving a thrust load (a load in a direction in which the orbiting scroll is axially separated from the fixed scroll) between the casing and the orbiting scroll, and preventing the self-rotation of the orbiting scroll on its axis.
Each of the aforementioned ball coupling devices according to the related art includes a pair of support members provided facing each other in the casing and the orbiting scroll, and a spherical ball provided for rotation between the support members. In this case, the ball supports the thrust load on the orbiting scroll and also prevents the self-rotation of the orbiting scroll on its axis.
In the related art, the thrust load on the orbiting scroll is supported and the self-rotation thereof is prevented at the same time by using the pair of support members for supporting the spherical ball for rotation. Thus, ball support surfaces (rolling surfaces) of the support members on which the ball rolls need to be accurately processed in both of an orbiting direction and an axial direction, and it is difficult to improve product yield.